Party-line telephone system



Jam. 29, 1929.

L. R. WALLER PARTY LINE TELEPHONE svs'wm Filed Aug. 10, 1926 //7V/7/0/. [ee 5 Wd//6/f by W Af/amey.

Patented Jan. 29, 1929.

lll iE STAT FATEJ T LEE n. WALLEB, or monrnnnn, QUEBEC, cannon; ASSIGNOR r0 BELL TELEPHONE nenonnronrns, rnoonro m'rnn, on NEW YORK, n, Y., A conronnrron on ew YORK.

PARTY-LINE TELEPHONE SYSTEM.

Application filed August 10, 1926. Serial No. 128,380.

This invention relates to telephone exchange systems and more particularly to party-line automatic telephone systems.

Ilt is the object of the invention to improve revertivc calling and particularly to economine in the use of equipment and to simplify the procedure on. the part of the subscriber.

Heretofore there have been two general methods of making such rcvertive connections. One of these methods employs means associated With the first selector of the train of switches used in establishing a connection for temporarily removing the busy condition from the multiple of the calling line, there: by enabling the connector switch to seize the called line and apply ringing current thereto in the same manner as though the desired station wereon a separate line. In practicing this method all of the switches employed in the connection are held during the entire conversational period and, of course, it is neces-, sary to supply special means in the first selector for removing the busy condition. In the second'method a special ring-back switch is employed which is selected by the first selec tor when the calling subscriber dials a special code. In practicing this method it is neces: sary for the calling subscriber to dial a spe cial code thereby digressing from the usual procedure in obtaining" line connections.

In accordance with the present invention it is necessary merely to dial the directory numher of the called subscriber, the connector be: in provided with a relay which operates only when the called line is the calling line to distinguish a revcrtive call from a direct call. According; to another aspect of the invention means is provided for giving the calling subscriber oral instructions when making a revertive call.

In making a revertive call with the connector switch of thepresent invention, when the connector comes to rest on the line and tests it for busy condition, a circuit is completed from the connector, over. the sleeve terminal or the called line which is also the calling line and thence over the release conductor, back to a relay in the connector. In response to the operation of this relay the subscriber is instructed to hang up his receiver, while rings ing takes place. This relay also alters the rin ging arrangement to cause the bells of both parties to be rung. The restoration of the receiver releases all the switches in the train used in buildine' up the connection, with the exception or the connector, which is held under the control of this same relay and serves to supply talkingcurrent to the line.

The operation of the connector switch embodying this invention will be more clearly understood from a consideration of the following description in connection with the drawing which shows such a connector switch n detail together with a diagrammatic show inn of means for establishing both a direct and a revertive connection.

Let it be assumed that the subscriber at sub-station 100 which is one of two on a party line, desires to call a subscriber not on the same line, he will remove his receiver from the hook whereupon the line switch 101 will extend the line to a first selector 102. The subscriber will then dial the number of the wanted subscriber and Selectors 10:2 and 103 will be positioned to connect the suhscriber s line with the connector shown in detail.

When second selector-103 comes toqreet on the terminals of the connector switch, a circuit is completed from battery, through the right winding of relay 10%, left normal contact of relay 105, over the tip conductor. of selectors 103 and 102 and line switch 101 through the sub-station 100 back over the ringconductor of line switch 101 and selectors 102 and 103, right normal contact of relay 105, left winding; of relay 104 to ground. Relay 104; closes an obvious circuit tor relay 106 which connccts ground from the outer-right back contact of relay 107 over the outer right front contact of relay 100 to release conductor 130 holding the train of switches. 10,6 llso prepares a circuit for vertical magnet 109 extending from battery through the winding of the magnet, winding of slow to release relay 110, normal contact 111, inner right front con: tact of relay 10.6, to theback contact of relay 104;.

l/Vhen the subscriber dials the third digit of the called number, relay 104g releases and com; pletes this circuit for magnet 109. The cone nector switch is moved upward in response to the operation of the vertical magnet 109 closing olhnornial contacts 112,113 and 11 1- and opening normal. contact 111. Belay 110 operates in series with magnet 109 and closes a second circuit for itself and magnet 109 over its right front contact and contact 113 to the contact of relay 106. Contact 113, is el d before contact 111 opens so that no dial pulses are lost. Magnet 109 advances the connectorone vertical step foneach dial pulse.

When the last pulse of the series has been received relay 101 remains operated for a sufficient length of time to permit relay 110 to release and prepare the circuit of rotary magnet 115. The circuit of magnet 115 extends over the outer left back contact of relay 116, outer left back contact of relay 107, back contact of relay 110, elf-normal contact 118, front contact of relay 106 to ground at the back contact of relay 10 1.

When relay 10 1 releases in response to the first pulse of the last digit, the above traced circuit is closed and magnet 115 operates to give the connector one rotary step. At the same time two circuits are closed in parallel with magnet 115 from battery through the winding of relay 11.8 and a second circuit from battery through the winding of relay 117'and the left normal contact of relay 118. Relay 118 operates and being slow to release holds its armatures attracted throughout the dfaling of the last digit. Relay 118 closes an obvious holding circuit for relay 117 which is also slow to release.

When relay 104: remains operated for a sufiicient length of time following the last pulse of the digit, relay 118 releases but relay 117 'does not release for a further interval. At this time a circuit is closed from battery through the winding and over the left normal contact of relay 107, back contact of relay 118, inner left back contact of relay 116, front contact of relay 117, to sleeve brush 119. If the called line is busy, ground will be connected to the sleeve terminal from the apparatus with which that line busy and relay 107 will operate, locking over its left front contact, outer right front contact of relay 106 to ground through the right winding of relay 124; and at the outer right back contact of relay 11'. as soon as that relay releases. Relay 124 does not operate in series with relay 107.

lVith relay 107 operated, a tone is transmitted through repeating coil 1 10, outer right front contact of relay 107, back contact of armature No. 3 of relay 124;, right winding of relay 105, left Winding of relay 125 to battery. This tone is transmitted through cendenser129 to the receiver at the subscribers substation notifying him that the called line is busy, whereupon he may hang up and re lease relays 104, 106 and 107 in turn operating release magnet 131 and restoring the con-- nector and other switches to normal.

Should the called line be idle, relay 10' will not operate and when relays 117 and 118 release, a circuit will be closed from battery through the cut-off relay, for example relay 121, terminal 120, brush 119, left back contact of relay 117, left winding of relay 116, inner right back contact of relay 107, outer right front contact of relay 106 to ground at the outer right back contact of relay 117. Relay 116 locks in a circuit from battery through its right winding and right front contact, middle right contact of relay 106 to ground. Relay 116 also connects ground over its inner left front contact directly to brush 119, holding the called line busy.

The operation of relay 116 completes the ringing circuit which extends from source of ringing current 122 through interrupter 123, back contact of the No. 2 armature of relay 124:, inner right back contact of relay 125, middle right front contact of relay 116, inner left back contact of relay 126, brush 127, ring conductor of the subscribers line through the bell of the called subscribers sub-station back over the tip conductor to brush 128, right back contact of relay 126, outer right front contact of relay 116, outer r ght back contact of relay 125, right winding of relay 125 to battery. The bell is rung intermittently under the control of the interrupter 123 but relay 125 does not operate in series with the ringer.

Had the called line been one on a party line, the ringer would have been connected between either the tip or ring conductor and ground. The multiple terminals correspondin to the different parties appear before different connectors, which connectors are arranged to apply the ringing current to the proper side of the line.

l/Vhen the called subscriber answers, relay 125 operates and locks in a circuit from battery through its left winding and inner left front contact to ground at the middle right contact of relay 106. Relay 125 in operating extends the calledsubscribefis line through the left winding of relay 105 to battery and through the right winding of relay 105 and the inner right front contact of relay to ground at the middle right contact of relay 106. The calling subscriber receives talking battery through the windings of relay 10 i and the called subscriber throu the windings of relay 105. I

1f, following conversation, the calling subscriber hangs up first, he will release relay 10% closing the previously traced circuit for relays 117 and 118 which relays operate, ineffectively. However, the circuit of relay 106 now remains open for a sufficient length of time for relay 106 to release. In releasing, relay 106 removes ground from the release conductor 130 and permits line switch 101 and selectors 102 and 103 to release. After the proper interval, relays 117 and 118 re lease and the circuit remains in this condition until the called party hangs up, Relay 105 being held operated by the called subscriber provides a substitute ground for holding relays 125 and 116 operated which may be traced from the locking contacts of these relays over the neXt to the innermost leftfront Hill Contact of relay 105, outer left front contact of relay 125, outer left front contact of relay 116 to ground. c

When the called subscriber restores his re; ceiver, relay 105 releases in turn releasing relays 125 and 116. WVith relay 105 released, the circuit of release magnet 131 is completed over off-normal contact 112, outer left back contact of relay 105, left back contact ofre lay 124, right back contact of relay 106, back contact of relay 104 to ground. The release magnet 131 operates and restores the connector switch to normal, opening the off-norma]. contacts and closing the normal contacts, in turn opening the circuit of the release magnet. s

If the called party hangs up first, relay 105 alone is released since relays 125 and 116 are held operated under the control of relay 106 which is in turn held operated by relay 104. When new the calling subscriber hangs up, relay 104 releases, in turn releasing relay 106. Since relay 105 has already been released, the circuit of the release magnet is immediately closed and the switch restored. The release of relay 106 also releases relays 125 and 116. Should the subscriber of sub-station 100 Wish to call another subscriber on his own line, he will dial the directory number of that subscriber in response to which selectors 102 and 103 will be positioned and the connector will direct its brushes to the multiple termi nals of the calling line appearing in its bank. Relays 118 and 117 are operated on th efirst pulse of the last digit as previously described. When relay 118 releases due to relay 104 re-' maining operated following the last digit, thepreviously traced circuit for relay 107 is completed. Since the called line is also the calling line, the sleeve terminal 132 will be grounded over back contact of relay 107 and through the winding of relay 124 by Way of the release conductor 130 and the release conductor extending through selectors 103 and 102 and finder 101. Relay 107, will therefore,

operate and lock as previously described. The operation of relay 107 will connect battery through low resistance 141, inner right front contact of relay 107, back contact of relay 118, inner left back contact of relay 116, front contact of relay 117 to sleeve brush 119, whence the circuit will be extended over terminal 132 back through the line finder and selectors 102 and 103, outer right front contact of relay 106 to the right winding of relay 124. Relays 107 and 117 being operated, the direct ground over their back contacts is removed and relay 124 operates. Relay. 12 4 locks in a circuit from battery through its.

right winding, right front contact, off-normal contact 114, middle left back contact of relay 105 to ground. As soon as relay 1 17 closes its back contact, direct ground is connected to the release conductor. i i i The operation of relay 12,4 completes a circuit from battery through the right wind ing of relay 104, contact of No. 6 armature of relay 124 through the winding of relay 133, contact of armature No. 7 of relay 124, left winding of relay 104 to ground. Relay 133 operates in this circuit and lights lamp to notify an operator that a revertivebonnection has been attempted. The operator then closes key 135 and informs the calling subscriber that he is attempting a call to another subscriber on his own line and must hang up his receiver in order to permit the bells to be rung. In an office Where a large number of party lines are used, a phonographic device may be substituted for the ope1'atoi"stel.e phone circuit and a relay such as relay 136 which corresponds to relay 133 may start the phonographic device to give to the calling subscriber the same instructions as the opera tor would give. 111 some instances it might be possible to merely apply the busy tone to the calling line, the subscriber being informed by printed instructions the numbers for which the busy tone is a signal to restore the receiver to the switchhook temporarily to permit the bells to be rung.

W hen the calling subscriber restores his receiver in response to instructions, relay 104 releases closing the-previously described cir cuit for relays 118 and 117. After an inte r-,

val relay 106 releases opening the locking'circult of relay 107. With relay 10.6 released and relay 117 operated, ground is removed from the release conductor 130 and the switches 101, 102 and 103 permitted to release. I release. A circuit is closed from battery through the cut-off relay 108 of the sub scribers sub station, sleeve terminal 132 and brush 119, left back contact of relay 117, left winding of relay 116, inner right back contact of relay 107, front contact of No. 5 armature of relay 124, inn-er. left back contact of relay 117 to ground. Relay 116 operates in this circuit and locks to ground at the front contact of the No. 1 armature of relay 124. Relay 116 connects direct ground to terminal 119 holding the line busy.

As soon as relay 124 operated, it closed a circuit from battery through the winding of.

After an interval relays 118 and 117 relay 126, front contact of the No. 4 arina- Y armature of relay 124,inner right backf'co ntact of relay 125,-middle right front contact of relay 116. to contacts of relay, 126, whence it extends alternately. over the tip and ring conductors of the subscribers line through the ringers 140. and 141, respectively, to

ground. As soon, as. relay 126. operates, this ringingcu ntis effective to ring the bellsof stations 150 and 100 alternately. A circuit is also preoared for relay 125 extending from battery, through the ri ht winding and outer right back contact of relay 125, outer right front contact of relay 116, over contacts of relay 126 to the opposite conductor to that to which ringing current is being applied.

When the called party answers, the ringing circuit is connected to the circuit of relay 125 and that relay operates and locks to ground over the No. 1 armature ct relay 12 1. .it also disconnects ringing current from the line and transfer; the circuit of relay 126 from interrupter 13'? to direct ground. operation of relay 125 applies talking batter to the line, the circuit extending from batt b tln'ougl'i the left winding of relay 105, outer right front contacts oi? relay 125 and relay 116, left front contact of relay l26,brush 127 to toe ring conductor, back over the tip conductor to brush 128, inner right ifront contacts of relays 126, 116 and 125, right winding of relay 105, inner left front contact of relay 125, to ground at the front contact oft armature No. 1 of relay 12 1. Belay 105 operates in this circuit and completes a subs itute holding circuit for relays 116 and 125 which may be traced "from ground at the outer left front contacts of relay 116 and relay 125, next to the inner left front contact of relay 105, to the armatures oi relays 125 and 116. It also closes a locking circuit for relay 126 which holds that relay operated during the conversation. In adoitic-n it opens the locking circuit of relay 124.- and that relay releases disconnecting relay 133 from relay 104;, opening one ground connection to leases, in turn releasing relays 116, 125

the release conductor 130, the operating circuit of relay 126, the ringing circuit and the locking circuit for relays 125 and 116. (l-round is still connected to release conductor 130 to mark the cormector busy to other second selectors, over the inner right back contact of relay 107, lettt whirling of relay 116, left bacl; contact of relay 117, to ground at the inner lolt front contact. oi relay 116.

The subscriber at sub-station hearing the cessation of ringing lmows that the called subscriber has answered. and also removes his receiver and conversation proceeds. As long as either receiver is oil the switchhool: relay will remain operated. llhen both rcceivers have been restored, relay 105 reand 126. As soon as relay 105 releases, the circuit of release magnet 181 is closed and that magnet causes the restoration of the switch to normal, opening tl'ie'oit-normal contacts and the circuit of the release magnet.

If the called subscriber fails to answer, the calling subscriber removes his receiver from the switchhook and replaces it, permitting the above described operations to take place to stop the ringing and release the connector.

Two supervisory circuits are provided which operate an alarm provided they re-- main closed an unusuallength of time. One of these circuits is used to indicate that the calling subscriber has not restored his receiver to the switchhook within a reasonable length of time following the restoration o1 the receiver by the called party. The other circuit indicates that the called party has not hun up within a reasonable length of time following the hanging up of the calling subscriber. It will be ren'iembered that the calling line holds relays 10 1 and 106 operated, in turn holding relays 125 and 116 operated and that the called line holds relay 105 operated. llherci ore when the called subscriber fails to hang up, circuit is completed from the alarm over the, outer lettt contact of relay 126, outer left frontcontact of relay 105, left back contact of relay 12 1, back contact oi relay 106, back contact of relay 10 1 to ground. W hen the called. subscriber hangs up, releasing relay 105, this circuit is opened.

When the calling subscriber fails to hang up, a circuit will be closed from the alarm over inner left back contact of relay 105, outer lett front contact of relay 125, outer left front contact of relay 116 to ground. lVheu the calling party hangs up, releasing relay 104, relay 106 will be released opening the loclzin circuit oi relays 125 and 116 and this supervisory circuit will be opened.

What is claimed is:

1. In a telephone system, subscribers lines including party lines, a connector switch. means for extending a connection from caling one of said party lines to said connector. means in said connector for completing said connection to a. called line, means for testing whether said line is busy or idle, and means in said connector operated in conjunction with said testing means when the calling and called parties are both on the same line lo.

permit the release oi said connection extend ing means while maintaining said connector in connection with said line.

2. 1n a. telephone systcn'i, subscribers lines including party lines, a connector switch, means for extending a connection from calling one of said party lines to said. connector, means in said connector for completing said connection to a called line, means for giving instructions to the calling subscriber,

and means in said connectoroperated when the calling and called parties are both on the same line to associate with said line said means for giving instructions to the calling subscriber.

3. In a telephone system, subscribers. lines including party lines, a connector switch, means for extending a connection from a calling one of said party lines to said connector, means in said connector for completing said connection to a called line, an operators telephone circuit, and means in said connector operated when the calling and called parties are both on the same line to associate said operators telephone circuit with said line for instructing the calling subscriber how to proceed to permit the completion of the connection.

4:. In a telephone system, subscribers lines including party lines, a connector switch, means for extending a connection from a calling one or said party lines to said connector, means in said connector lor completing said connection to called subscribers line, means for giving instructions, means in said connector operated when the calling and called subscribers are both on the same line to associate said instructing means with said line to instruct the calling subscriber to restore his receiver to permit signaling to take place, and means operated following the restoration of the receiver to the switchhook to release said connection extending means and to retain said connector in connect-ion with said line.

5. In a telephone system, subscribers lines including party lines, a connector switch, means for extending a connection from a calling one oi. said party lines to said connector, means in said connector for completing said connection to a called subscribers line, means for giving instructions, means in said connector operated when the calling and called subscribers are both on the same line to associate said instructing means with said line to instruct the calling subscriber to restore his receiver to permit signaling to take place, means operated following the restoration of the receiver to the switchhook to release said connection extending means and to retain said connector in connection with said line, and means to apply ringing current alternately to the tip and ring of said line over the brushes of said connector to rin the bells of both parties on said line.

6. In a telephone system, subscribers lines including party lines, a connector switch, means for extending a connection from a calling one of said party lines to said connector, means in said connector for complet ing said connection to a called line, means to test whether said line is busy o-ridle, a relay in said connector operated in conjunction with said testing means when the calling and called subscribers are both on the same line, and means under the control of said relay to permit the release of said connection extending means while maintaining said connector in connection with said line.

7. in a telephone system, a party line, a connector switch, other switching means for extending a connection from said line to said connector, multiple terminals for said line appearing before said connector, a third terminal associated with said line terminals, a release conductor connected with said third terminal and extending through said switching means to said connector, means to position the brushes of said connector on the terminals of said line, a relay in said connector operated over said release conductor in acircuit completed dver said third terminal by said connector, and means under the control of said relay to release said switching means while maintaining the brushes of said connector in position on the terminals of said line.

8. In a telephone system, a party line, a connector switch, other switchingmeans for extending a connection from said line to said connector, multiple terminals for said line appearing before said connector,a thirdterminal associated with said line terminals, a release conductor connected with said third terminal and extending through said switching means to said connector, means to position the brushes of said connector on the terminals of said line, a relay in said connector operated over said release conductor in a circuit completed over said third terminal by said connector, means for giving instructions to a subscriber, and means under the control of said relay to associate with said line said means for giving instructions.

9. In a telephone system, a party line, a connector switch, other switching means for extending a connection from said line to said connector, multiple terminals for said line appearing before said connector, a third terminal associated with said line terminals, a release conductor connected with said third terminal and extending through said switching means to said connector, means to position the brushes of said connector on the terminals of said line, a relay in said connector operated over said release conductor in a circuit completed over said third terminal by said connector, an operators telephone circuit, and means under the control of said relay to associate said telephone circuit with. said line for giving instructions to the calling subscriber.

10. In a telephone system, a party line, a connector switch, other switching means for extending a connection from said line to said connector multiple, terminals for said line appearing before said connector, a third terminal associated with said line terminals, a release conductor connected with said third terminal and extending through said switching means to said connector, means to position the brushes of said connector on the terminals of said line, a relay in said connector operated over said release conductor in a circuit completed over said third terminal by said connector, means for giving instructions, means under the control of said relay to associate said instructing device with said line to instruct the calling subscriber to restore his receiver to permit signaling to take place, and means operated following the restoration of the receiver to the switchhook to release said connection extending means connector, multiple terminals for said line appearing )e'fore said connector, a third terminal associated With said line terminals, a release conductor connected with said third terminal and extending through said switehing means to said connector, means to position the brushes oi said connector on the terminals of said line, a relay in said connector operated over said release conductor in a circuit completed over said third terminal by said connector, means for giving 1nstructions, means under the controlof said relay to associate said instructing means With'said line to instruct the calling subscriber to restore his receiver to permit signaling to take place, means operated following the restoration of the receiver to the switchhook to release said connection extending means and to retain the brushes of said connector on the multiple terminals oi said line, and means to apply ringing current alternately to the tip and ring of said line over the brushes of said connector to ring the ells of both parties on said line.

In Witness whereof, I hereunto subscribe my name this 4th day of August, A. D. 1926.

7 LEE R. WALLER. 

